“I think one would want to understand in some detail. . . why would it be between four and 10 times more expensive for NASA to do this, especially at a time when one of the issues facing NASA is how to develop the heavy-lift launch vehicle within the budget profile that the committee has given it,” Chyba says. He cites an analysis contained in NASA’s report to Congress on the market for commercial crew and cargo services to LEO that found it would cost NASA between $1.7 billion and $4 billion to do the same Falcon-9 development that cost SpaceX $390 million. In its analysis, which contained no estimates for the future cost of commercial transportation services to the International Space Station (ISS) beyond those already under contract, NASA says it had “verified” those SpaceX cost figures. For comparison, agency experts used the NASA-Air Force Cost Model—“a parametric cost-estimating tool with a historical database of over 130 NASA and Air Force spaceflight hardware projects”—to generate estimates of what it would cost the civil space agency to match the SpaceX accomplishment. Using the “traditional NASA approach,” the agency analysts found the cost would be $4 billion. That would drop to $1.7 billion with different assumptions representative of “a more commercial development approach,” NASA says.

The SpaceX experience of developing a launcher in the Falcon 9 at 1/10th the cost of a government financed one also holds for the crew capsule development costs since the Dragon capsule cost about $300 million to develop while the Orion costs several billion and still counting. So it can't be said this cost saving is just due to the Falcon 9 being, so far, unmanned. Speaking about Orion and billions of dollars, I read an article about plans to use the Orion on the Ariane 5 to get a European manned spaceflight capability:

This would cost several billion dollars to man-rate the Ariane 5. I have to believe the solid rocket boosters, which can not be shut down when started, play a significant role in that high cost. The article mentions also the core stage would have to be strengthened. But such strengthening is based on it having to support a 20 mT Orion capsule and a 20 mT upper stage which wouldn't be used with a much smaller capsule such as the Dragon, at a dry mass of about 4 mT. Note also that quite likely an even smaller manned capsule could be designed at about a 2 mT dry mass to carry a 3 man crew, which given its half size compared to the Dragon, might cost in the range of only $150 million to develop as privately financed. It's hard to imagine that private investment could not be found to finance such a capsule development when it could lead to a manned European space capability. In regards to the costs of a privately financed SSTO version of the Ariane launcher we might make a comparison to the Falcon 9. It cost about $300 million to develop and this includes both the structure and engines, the engines making up the largest share of the development cost of a launcher. But for the SSTO Ariane both engine and structure are already developed and it's only a single stage instead of the two stages of the Falcon 9. You would have the development cost of adding 2 additional engines and of the new avionics, but again I have to be believe the development cost would once again be less than the SpaceX development cost of the Falcon 9 if privately financed.

I also read that the ESA is attempting to decide whether to upgrade the Ariane 5 or move to a Next Generation Launcher(NGL):

If the NGL is chosen then a quite expensive new large engine development would have to be made, and the launcher might not enter service until 2025. In contrast the SSTO-Ariane, given that the engine and stage already exist, a prototype probably could be ready within 1 to 2 years, and moreover by using a second stage it could also be used to launch the medium sized payloads.

So the SSTO-Ariane would solve the twin problems at low cost of providing Europe with a manned spaceflight capability and giving it a lower cost medium lift capability.

WSJ: Europe Ends Independent Pursuit of Manned Space Travel."LE BOURGET, France—Europe appears to have abandoned all hope ofindependently pursuing human space exploration, even as the region'spoliticians and aerospace industry leaders complain about shrinkingU.S. commitment to various space ventures."After years of sitting on the fence regarding a separate, pan-European manned space program, comments by senior government andindustry officials at the Paris Air Show here underscore that budgetpressures and other shifting priorities have effectively killed thatlongtime dream."http://www.orbiter-forum.com/showthread.php?t=23006

In this post I discussed getting a SSTO by replacing the Vulcainengine on the Ariane 5 core with a SSME:

However, in point of fact Europe can produce a manned launch vehiclefrom currently *existing*, European components. This will consist ofthe Ariane 5 and three Vulcain engines. The calculations below use theAriane 5 generic "G" version. You might need to add another Vulcainfor the larger evolution "E" version of the Ariane 5 core. In a following post I'll also show that the Hermes spaceplane alsocan become a SSTO by filling the entire fuselage aft of the cockpitwith hydrocarbon propellant. The impetus for trying the calculation for a Ariane 5 core based SSTOusing Vulcains instead of the SSME was from a report by SpaceX thatyou could get the same performance from a planned heavy lift firststage using a lower performance Merlin 2 compared to the highperformance RS-84 engine. The reason was the lower Isp of the Merlinwas made up for by its lower weight.

THIS IS A VERY IMPORTANT FACT BECAUSE WHAT IT MEANS IS THAT YOU DON'TNEED THE HIGH PERFORMANCE ENGINES TO GET THE SSTO. YOU CAN USE ENGINESOF LOWER CHAMBER PRESSURE AND SIMPLER COMBUSTION CYCLES, SUCH AS THEVULCAIN WITH A CA. 100 BAR COMBUSTION PRESSURE AND A GAS GENERATORCYCLE. THIS MEANS THE ENGINES ARE CHEAPER, EASIER TO MAKE REUSABLE,REQUIRE LESS ROUTINE MAINTENANCE, AND CAN LAST FOR MANY RESTARTS.

In the discussion of the Ariane/Vulcain SSTO below, I note you canget a prototype, test vehicle quite quickly since the components arealready existing. To improve the payload though you would want to usealtitude compensation on the Vulcains. In a following post I'lldiscuss some methods of altitude compensation. In regards to achieving this at low cost, I think the most importantaccomplishment of SpaceX might turn out to be that they showed instark terms that privately financed spacecraft, both launchers andcrew capsules, can be accomplished at 1/10th the developmental cost ofgovernment financed ones. Imagine a manned, reusable orbital launcher,for example, instead of costing, say, $3 billion, only costing $300million to develop. Here's how you can get an all European manned SSTO using the Ariane 5core stage but with Vulcain engines this time. Note that this is onethat can be produced from currently existing components, aside fromthe capsule, so at least an unmanned prototype vehicle can bemanufactured and tested in the short term and at lowered developmentcost. We'll use three Vulcain 2's instead of the 1 normally used with theAriane 5 core stage. There are varying specifications given on theVulcain 2 depending on the source. I'll use the Astronautix site:

From the sea level thrust given there, using three Vulcain 2's willgive us one engine out capability. The weight is given as 1,800 kg. Soadding on two will take the dry mass from 12 mT to 15.6 mT. To calculate the delta-V achieved I'll use the idea again to just usethe vacuum Isp, but adding the loss due to back pressure onto thedelta-V required for orbit, as I discussed previously. However, herefor hydrogen fuel which has higher gravity loss, I'll use a higherrequired delta-V of 9,400 m/s when you add on the back pressure loss.With the vacuum Isp given for the Vulcain 2 of 434 s, we get a payloadof 3.8 mT:

434*9.8ln(1+158/(15.6+3.) = 9,412 m/s.

Note this is just using the standard nozzle Isp for the Vulcain, noaltitude compensation. So this could be tested, like, tomorrow. However, for a SSTO you definitely want to use altitude compensation.Using engine performance programs such as ProPEP we can calculate thatusing long nozzles, you can get a vacuum Isp of 470 s for this engine.As a point of comparison of how high an Isp you can get even with alow chamber pressure engine as long as you have a long nozzle, orequivalent, note that the RL10-B2 with a ca. 250 to 1 area ratio, andonly a ca. 40 bar chamber pressure, gets a 465 s vacuum Isp. So we'llassume we can get a comparable Isp by using altitude compensation.This allows us to get payload of 8 mT:

470*9.8ln(1+158/(15.6+8) = 9,400 m/s.

This allows us to add a Dragon-sized capsule and also the reentry andlanding systems to make it reusable.

_________________Single-stage-to-orbit was already shown possible 50 years ago with the Titan II first stage. Contrary to popular belief, SSTO's in fact are actually easy. Just use the most efficient engines and stages at the same time, and the result will automatically be SSTO.Blog: http://exoscientist.blogspot.com

Since Arianespace recently started launching Soyuzes, why not just get the manned version of that? The whole launch infrastructure is already there and in operation, and putting a 3-man capsule on top of Ariane 5 certainly wouldn't make sense from a cost perspective compared to Soyuz and F9. I guess the actual rockets are manufactured in Russia though, so if they wanted a fully European system then they'd have to set up a factory. But the Russians were happy to sell the technology to China, so why not to Europe? And then why not use a tried-and-true system rather than develop something new and much more expensive?

_________________Say, can you feel the thunder in the air? Just like the moment ’fore it hits – then it’s everywhereWhat is this spell we’re under, do you care? The might to rise above it is now within your sphereMachinae Supremacy – Sid Icarus

The CST-100 crew capsule is largely privately financed by Boeing, though they have gotten some commercial crew development dollars from NASA as has SpaceX. This is a very important point that the CST-100 is primarily privately financed. I can guarantee you Boeing is not spending several billion dollars of their own money developing the CST-100 like what Orion is costing using government money. (Note to Boeing: come up with a better name for your capsule.)

My guess is that it's costing a few hundred million dollars tops, comparable to what the Dragon cost SpaceX to develop. Note this once again means a privately financed spacecraft can be developed for 1/10th the cost of a government financed one. That Boeing was able to do this just as SpaceX has done overwhelmingly implies this is valid as a general principle. Note this also strongly implies that the large launch providers such as Boeing can produce a launcher capable of manned flight as privately financed for 1/10th the cost of the billion dollar estimates given for such launchers, so in the few hundred million dollar range, just as SpaceX has done with the Falcon 9.

This also strongly implies the same is true for the space programs in other countries. In this thread I argue the ESA could produce a manned launcher for a few hundred million dollars if privately financed. On another forum, it was argued the same kind of cost savings SpaceX made wouldn't apply in this case.

However, the ESA is a government organization which supplies government finances from the ESA member countries to the private companies that build the Ariane 5 launcher. Then all that would be required is that the ESA also, like NASA, make a proposal of European aerospace companies to privately develop launchers and spacecraft, perhaps with some amount of seed money as NASA is doing, and that the ESA would make a commitment to purchase such launchers and spacecraft even if such launchers undercut the prices of the Ariane 5.

Note that Boeing originally lost out to Lockheed to build the Orion capsule. But with the CST-100 it will be able to make more manned launches to orbit, at an earlier start date, and at much reduced cost than the Orion. And in fact, several different companies will now have the opportunity to offer manned launch services to NASA.

The same would be true of the European aerospace companies, to allow several different companies to operate offering launch and spacecraft services to the ESA, not just EADS Astrium with the Ariane 5. This will have the effect of increasing the European space industry not reducing it.

Bob Clark

_________________Single-stage-to-orbit was already shown possible 50 years ago with the Titan II first stage. Contrary to popular belief, SSTO's in fact are actually easy. Just use the most efficient engines and stages at the same time, and the result will automatically be SSTO.Blog: http://exoscientist.blogspot.com

So the SSTO-Ariane would solve the twin problems at low cost of providing Europe with a manned spaceflight capability and giving it a lower cost medium lift capability.

Actually, it doesn't have to be a SSTO. I was arguing for using a much smaller capsule than the Orion for then you wouldn't need the full Ariane 5 launcher, with the two large strap on boosters, so it would be easier and cheaper to man-rate.

If you still give the Ariane 5G core stage two additional Vulcain 2's, then you can lift greater payload using an upper stage than with the SSTO version. You would need to include the mass of the interstage in this case to support the weight of the upper stage and payload, call it 1,000 kg for the interstage.

In the calculation I'll use the 15.6 mT dry mass I used before for the Ariane 5G with the two extra Vulcain 2's and again a 434 s Isp for the Vulcain 2. I'll get the specifications for the LH2/LOX upper stage also from the SpaceLaunchReport page on the Ariane 5, at a 19.4 mT gross mass, 14.9 mT propellant load, 4.5 mT dry mass, and 446 s Isp of the upper stage cryogenic engine. I also include in the calculation 1 mT for the interstage that will be in the first stage delta-V calculation only since it is jettisoned along with the first stage. Then you could lift ca. 10 mT to orbit:

This could then loft a Dragon sized capsule. It could also loft the Boeing CST-100 capsule and the Sierra Nevada Dream Chaser since these are both planned to be launched by the Atlas V version without the side boosters, which has a ca. 10 mT LEO payload capability.

So this could compete for those launches of these manned spacecraft planned now only to be carried by either the Falcon 9 or Atlas V. This launcher again should have comparatively low development cost since the engines and stages are already developed and you would have only the development cost of adding on the two engines and the new avionics.

This option should be more palatable to the ESA since it avoids the controversial SSTO's. Of course at some point it would be realized, "Hmm, if we made the capsule half the size of those other ones to carry just three people then that first stage by itself could carry it, and we wouldn't have that extra expense of the upper stage ..."

Bob Clark

_________________Single-stage-to-orbit was already shown possible 50 years ago with the Titan II first stage. Contrary to popular belief, SSTO's in fact are actually easy. Just use the most efficient engines and stages at the same time, and the result will automatically be SSTO.Blog: http://exoscientist.blogspot.com

Isn't SpaceX developing their own booster to lift Dragon? We're still a long way off from a true OStEO (One Stage to Earth Orbit) without a working Aerospike, or other engine that works efficiently at all altitudes. A breakaway nozzle might work as a hybrid, not quite extra stages for the complexity, and weight involved.

For those not familiar, the most efficient nozzle for low altitudes is a parabola with a long deep bell, while as you get higher, less of the walls are neccessary without the external air pressure. Therefore, 1 engine could theoretically be used with ring sections which could be dropped, or ablate away as they are no longer needed, taking their weight with them. I don't think a heat exchanger nozzle would work with such a design, except in the final dish of the noszzle for the actual orbital leg of the trip.

While not a true OStEO, it would be a lot less mass, and complexity than multiple engines, sections, and tanks used in the traditional multistage stack.

_________________"You can't have everything, where would you put it?" -Steven Wright.

Er, yes. Falcon 9. It's already launched a Dragon, so 'working on' isn't the best description. Another launch planned next month to test delivery to the ISS.They also plan to make the stages reusable, which sort of negates the need for SSTO. Plan seems pretty feasible to me, but I'm not a rocket scientist.

Testing is part of developing, or at least it should be in something as critical, and dangeroous as spaceflight. When they start routine flights for purposes other than R&D, i'll concider it a working model. SpaceX seems to have a similar view, which is why I like them most out of all the private startups. They seem to be doing it right.

_________________"You can't have everything, where would you put it?" -Steven Wright.

My opinion, but I don't think any launcher ever made has really got past the development stage. I'm guessing, but I would think something has changed/improved after every single launch of every single rocket. There simple are not enough flights to have reached the routine stage.

Hello. I was interested to read your report, "(titled deleted)" from July 2011. On page 65 it states:

"The HHSC appears as the most promising launch concept:– The current design clearly shows the advantages of a single High Thrust Engine approachyielding less costly propulsion systems."

Other reports I read also suggest producing a staged combustion engine at about twice the thrust of the Vulcain. This would be a large engine at about the thrust of the space shuttle main engines(SSME) using also the complex and expensive staged combustion cycle of the SSME. The SSME of course was quite an expensive development process for the U.S. How convenient for EADS Astrium and the other Ariane 5 contractors that the recommended format for the NGL is the most expensive one!

The idea that this would be a less expensive proposal than using just two or three Vulcains on the Ariane 5 core stage is highly dubious. In your report and in other reports I've seen this claim is simply stated without given any comparison to the multi-engine Vulcain case. This in itself is highly questionable. I have to wonder why the multi-Vulcain approach among all those various other ones that are considered is not even evaluated.

Your report stated the single engine concept has proven to be less costly. Really? With ArianeSpace requiring a 100 million Euro subsidy every year, without which it would go bankrupt?? Every other space agency in the world, the U.S., Russia, China, India, has found it cost effective to use multi-engine stages. It is highly dubious that the ESA has discovered a great cost saving approach in always using a single engine that no other space agency grasps, yet at the same time ArianeSpace has to be propped up by megamillions every year because this approach has not proven to be cost effective.

I've seen in other reports an attempt to compare this EADS Astrium suggestion (I call it that because it appears that what's most beneficial to EADS Astrium is what's most beneficial to the ESA) to the Delta-IV model. That argument does not hold water either. The Delta-IV could have been launched using two SSME's. However, the SSME is a quite expensive engine meant to be reusable with high thrust using the most expensive cycle in staged combustion. The U.S. developed the RS-68 for the Delta-IV to get an expendable engine with fewer parts and using the simpler and cheaper gas generator cycle, the same cycle the Vulcain uses. It is also important to note in regards to cost it is only 1 and 1/2 times the thrust of the SSME, not twice the thrust, which also saved on cost.

But with the suggestion to develop a staged combustion engine at twice the thrust of the Vulcain, the ESA is reversing this logic. Because this engine will be using the most expensive combustion cycle while having twice the thrust of the Vulcain it very likely will cost more than two Vulcains, *plus* you have added on that very large development cost for this large engine.

Another argument made for the large, high performance engine is that it gives options in the size of the payloads launched. For instance, the cores could be combined a la the Delta Heavy. However, the multi-engine Ariane also has this capability. In fact, as a single stage it could launch small payloads also, giving ArianeSpace another market for launches. I have also done a preliminary calculation that two such cores with the usual Ariane 5 upper stage could launch ca. 16 mT. And with cross-feed fueling, which can increase payload about 25%, you could get the 20 mT capability of the current Ariane 5.

An additional big problem with the large, expensive single engine approach is that it is expected to come into use in the 2020 to 2025 time frame. The multi-Vulcain approach on the other hand probably could be implemented within 2 to 3 years. I would have no objection to the larger, higher performance engine being used at that later time for a *larger* stage as long as for *now* the multi-Vulcain approach is used.

It might be objected the ESA could not afford both. But SpaceX has shown that as largely privately financed launchers can be developed for markedly reduced costs than for government developed ones. It was able to develop the nine engine, not just two or three, Falcon 9 for ca. $300 million, and this included the costs of developing a whole new engine and a whole new stage. It is larger in all of number of engines, payload capacity, gross mass, dry mass, number of stages, etc. than the multi-Vulcain Ariane core stage would be. Plus there is also the key fact the engine and stage already exist for the multi-Vulcain so you don't have that development cost.

Quite frankly if EADS Astrium couldn't figure out how to add on one to two engines onto the Ariane 5 core *privately financed* for less than the $300 million SpaceX spent to develop the *entire* Falcon 9, then they are doing something wrong and should ask SpaceX to do it for them. But there is no doubt in my mind that the European engineers are at least as smart as the SpaceX engineers if not smarter and can do it in a low cost fashion if they have to.

Yes, if they have to. EADS Astrium and the ESA are in a partnership. The ESA needs EADS Astrium for their launchers and spacecraft, but EADS Astrium needs the ESA for its aerospace division. Then one way the ESA could encourage EADS Astrium to privately finance the conversion of the Ariane core to multi-engines is to agree to pay for the development of the larger, higher performance engine for that later time frame.

Considering the size of the Ariane core stage compared to the entire Falcon 9 rocket, I suspect this conversion could be done, privately paid for, for under $100 million, really no problem at all for EADS Astrium to finance it themselves. But there is a very important way EADS Astrium could attract financing from outside investors. Reports recently are that Europe has given up on plans of an indigenous manned spaceflight capability because of cost. But SpaceX has shown and NASA has confirmed with its commercial crew program that manned launchers and spacecraft can be developed for costs in the few hundred million dollars range as privately financed, perhaps with governmental seed money.

Then a quite important advantage of the multi-Vulcain Ariane approach is that both the single stage and two stage versions can be used for manned launchers. So this would provide Europe with a manned spaceflight capability at a short time frame and at low cost. This is clearly something that could attract outside investors.

To summarize, the ESA should make a public accounting of the comparison of the multi-Vulcain approach compared to the new large, expensive engine approach for a new launcher. Evidence from other space agencies suggests the multi-engine approach can be cost effective. The ESA should encourage EADS Astrium to privately finance the conversion. Lastly, and most importantly, the multi-engine approach can provide Europe with a manned spaceflight capability in a short time frame.

_________________Single-stage-to-orbit was already shown possible 50 years ago with the Titan II first stage. Contrary to popular belief, SSTO's in fact are actually easy. Just use the most efficient engines and stages at the same time, and the result will automatically be SSTO.Blog: http://exoscientist.blogspot.com

----------------------------------------------------------------------------------------------------------------- Hello. I saw your IAF reports on the H-II and proposed H-III launchers. Ithought you might be interested in the letter to the ESA copied below. The keyquestion is one of cost. I looked up references on the H-II rocket since Iremembered it was hydrogen-fueled to see if it could be SSTO. I was surprisedto see that JAXA in upgrading the H-IIA to the H-IIB, that they converted thesingle engine on the first stage to two-engines. Contrary to the ESA, they didthis to save on costs rather than developing a whole new, larger engine:

The development cost for the conversion was 27 billion yen. But 5 billion yenof this was paid for by Mitsubishi Heavy Industries as prime contractor asdescribed in the second article. Note also that this 5 billion yen costinvolved increasing the width of the tanks, which wouldn't be needed in theAriane 5 case. It is known that increasing the width of the tanks involves asignificant cost increase. Then we might estimate the cost as 22 billion yen,or $194 million by the exchange rate used in the second article without thistank width change. This is about what the ESA gave ArianeSpace last year as asubsidy. Note also JAXA was using the opposite of the financing ratio suggested by theSpaceX success and NASA's commercial crew program success, with most of thecost being paid for by the government and only a fraction being paid for byprivate financing. Following the SpaceX model of the majority of the cost being privatelyfinanced, we might expect the cost to be cut by a factor of 5 to 10, so toonly $20 to $40 million for the conversion in the Ariane 5 case.

I was interested to see in one of your IAF reports you discussed thepossibility of manned launchers. I see also that you intend to make the H-IIIbe all liquid fueled. Solid-rocket boosters are problematical for mannedlaunchers because they can not be shut down. Perhaps you intend to use theH-III for the purpose in that future time frame when it comes into use. However, the H-IIB core stage can be a SSTO manned launcher in the currenttime frame with small modifications. First the H-II core is not as well weightoptimized as the Ariane 5 core. You can improve that by using common bulkheaddesign as used by the Ariane. Note this is a well understood lightweightingmethod at this point, having been used back in the 1960's on the Apollocryogenic upper stages. Also, SpaceX has used it very effectively to give theFalcon 9 first stage a 20 to 1 mass ratio. You could also use aluminum-lithium alloy for the H-IIB core. This would cutan additional 25% off the dry mass of the structure aside from the engines.This would then give your stage an advantage over the Ariane 5 core since italso does not currently use aluminum-lithium. These structural changes are relatively low cost when you already have thetooling in place for a certain diameter tank. You still though would have todecrease the propellant load to lift off with only the two engines on thestage without the side boosters. You can just fill the tanks partially to say158 mT load, as used for example on the original version of the Ariane 5 core.It would not cost too much to also cut down the length of the tanksspecifically for the 158 mT load. Lengthening or shortening tank size is nottoo expensive as long as you use the same tooling for the same tank diameter. However, you might also choose to add a third engine onto the core instead ofreducing the propellant load. This probably can be done for comparably lowcost or even less than adding the second one since you don't have the extraexpense of re-tooling for wider tank size. In short JAXA, can in a short time frame join the group of manned spaceflight agencies and at relatively low cost. Also at being the first todemonstrate a SSTO vehicle JAXA will have accomplished a technical feat inimportance perhaps to rival Robert Goddards first flights with liquid-fueledrockets. The ESA already has the lightweight stages and moderately high efficiencyengines to do it. All they need to do is make the politically controlleddecision to add on a second engine to the Ariane 5 core stage. JAXA has theadvantage though in having already added on the second engine, and having moreefficient engines.

The only question now is who will be first to make the quantum leap to SSTOlaunchers.

Bob Clark

========================================================================== Hello. I was interested to read your report, "(title deleted)"from July 2011. On page 65 it states:

"The HHSC appears as the most promising launch concept:– The current design clearly shows the advantages of a single High ThrustEngine approachyielding less costly propulsion systems."

Other reports I read also suggest producing a staged combustion engine atabout twice the thrust of the Vulcain. This would be a large engine at aboutthe thrust of the space shuttle main engines(SSME) using also the complex andexpensive staged combustion cycle of the SSME. The SSME of course was quite anexpensive development process for the U.S. How convenient for EADS Astrium andthe other Ariane 5 contractors that the recommended format for the NGL is themost expensive one! The idea that this would be a less expensive proposal than using just two orthree Vulcains on the Ariane 5 core stage is highly dubious. In your reportand in other reports I've seen this claim is simply stated without given anycomparison to the multi-engine Vulcain case. This in itself is highlyquestionable. I have to wonder why the multi-Vulcain approach among all thosevarious other ones that are considered is not even evaluated. Your report stated the single engine concept has proven to be less costly.Really? With ArianeSpace requiring a 100 million Euro subsidy every year,without which it would go bankrupt?? Every other space agency in the world,the U.S., Russia, China, India, has found it cost effective to usemulti-engine stages. It is highly dubious that the ESA has discovered a greatcost saving approach in always using a single engine that no other spaceagency grasps, yet at the same time ArianeSpace has to be propped up bymegamillions every year because this approach has not proven to be costeffective. I've seen in other reports an attempt to compare this EADS Astrium suggestion(I call it that because it appears that what's most beneficial to EADS Astriumis what's most beneficial to the ESA) to the Delta-IV model. That argumentdoes not hold water either. The Delta-IV could have been launched using twoSSME's. However, the SSME is a quite expensive engine meant to be reusablewith high thrust using the most expensive cycle in staged combustion. The U.S.developed the RS-68 for the Delta-IV to get an expendable engine with fewerparts and using the simpler and cheaper gas generator cycle, the same cyclethe Vulcain uses. It is also important to note in regards to cost it is only 1and 1/2 times the thrust of the SSME, not twice the thrust, which also savedon cost. But with the suggestion to develop a staged combustion engine at twice thethrust of the Vulcain, the ESA is reversing this logic. Because this enginewill be using the most expensive combustion cycle while having twice thethrust of the Vulcain it very likely will cost more than two Vulcains, *plus*you have added on that very large development cost for this large engine. Another argument made for the large, high performance engine is that it givesoptions in the size of the payloads launched. For instance, the cores could becombined a la the Delta Heavy. However, the multi-engine Ariane also has thiscapability. In fact, as a single stage it could launch small payloads also,giving ArianeSpace another market for launches. I have also done a preliminarycalculation that two such cores with the usual Ariane 5 upper stage couldlaunch ca. 16 mT. And with cross-feed fueling, which can increase payloadabout 25%, you could get the 20 mT capability of the current Ariane 5. An additional big problem with the large, expensive single engine approach isthat it is expected to come into use in the 2020 to 2025 time frame. Themulti-Vulcain approach on the other hand probably could be implemented within2 to 3 years. I would have no objection to the larger, higher performanceengine being used at that later time for a *larger* stage as long as for *now*the multi-Vulcain approach is used. It might be objected the ESA could not afford both. But SpaceX has shown thatas largely privately financed launchers can be developed for markedly reducedcosts than for government developed ones. It was able to develop the nineengine, not just two or three, Falcon 9 for ca. $300 million, and thisincluded the costs of developing a whole new engine and a whole new stage. Itis larger in all of number of engines, payload capacity, gross mass, dry mass,number of stages, etc. than the multi-Vulcain Ariane core stage would be. Plusthere is also the key fact the engine and stage already exist for themulti-Vulcain so you don't have that development cost. Quite frankly if EADS Astrium couldn't figure out how to add on one to twoengines onto the Ariane 5 core *privately financed* for less than the $300million SpaceX spent to develop the *entire* Falcon 9, then they are doingsomething wrong and should ask SpaceX to do it for them. But there is no doubtin my mind that the European engineers are at least as smart as the SpaceXengineers if not smarter and can do it in a low cost fashion if they have to. Yes, if they have to. EADS Astrium and the ESA are in a partnership. The ESAneeds EADS Astrium for their launchers and spacecraft, but EADS Astrium needsthe ESA for its aerospace division. Then one way the ESA could encourage EADSAstrium to privately finance the conversion of the Ariane core tomulti-engines is to agree to pay for the development of the larger, higherperformance engine for that later time frame. Considering the size of the Ariane core stage compared to the entire Falcon 9rocket, I suspect this conversion could be done, privately paid for, for under$100 million, really no problem at all for EADS Astrium to finance itthemselves. But there is a very important way EADS Astrium could attractfinancing from outside investors. Reports recently are that Europe has givenup on plans of an indigenous manned spaceflight capability because of cost.But SpaceX has shown and NASA has confirmed with its commercial crew programthat manned launchers and spacecraft can be developed for costs in the fewhundred million dollars range as privately financed, perhaps with governmentalseed money. Then a quite important advantage of the multi-Vulcain Ariane approach is thatboth the single stage and two stage versions can be used for manned launchers.So this would provide Europe with a manned spaceflight capability at a shorttime frame and at low cost. This is clearly something that could attractoutside investors.

To summarize, the ESA should make a public accounting of the comparison ofthe multi-Vulcain approach compared to the new large, expensive engineapproach for a new launcher. Evidence from other space agencies suggests themulti-engine approach can be cost effective. The ESA should encourage EADSAstrium to privately finance the conversion. Lastly, and most importantly, themulti-engine approach can provide Europe with a manned spaceflight capabilityin a short time frame.

_________________Single-stage-to-orbit was already shown possible 50 years ago with the Titan II first stage. Contrary to popular belief, SSTO's in fact are actually easy. Just use the most efficient engines and stages at the same time, and the result will automatically be SSTO.Blog: http://exoscientist.blogspot.com

My primary complaint about the published plans for the ESAnext generation launcher and/or Ariane 6 was that the liquid fueledversion was to use a single, new expensive staged-combustion engine atabout twice the thrust of the Vulcain.I was therefore pleased to see that there is now being considered aversion that will use two engines on the core:

CNES, ASI Favor Solid-Rocket Design For Ariane 6.By Amy Svitak.Source: Aviation Week & Space Technology.October 15, 2012.Amy Svitak Naples, Italy, and Paris."Bonnal says CNES is preparing wind-tunnel tests to adjust the marginpolicy, and pressure oscillation has been assessed for differentflight phases."Similar to the P1B, the all-liquid H2C would use up to six strap-onboosters to carry as much as 8,400 kg to GTO. Twin main engines,capable of 150 tons of vacuum thrust derived from the Ariane 5'sSnecma-built Vulcain 2, would comprise the H165 first stage, whichwould be topped by a 31-ton cryogenic upper stage, he says. "http://www.aviationweek.com/Article.asp ... 16.xml&p=3

However, it seems to be the nature of governmental space agencies toalways want to go grandiose, like NASA. Instead of incurring the costof increasing the thrust of the Vulcain 2, why not use the same ones,use a smaller upper stage (31 tons really??) and go with the smallerAriane 5 "G" version of the core stage?As I discussed before, judging by the Japanese example withthe H-II rocket of adding on a second cryogenic engine, thismodification of the Ariane 5 core to use two Vulcains probably can bedone in the $200 million range. Then there really is no need tocontinue talking about billion dollar development programs for theAriane 6.Indeed with the recent ESA decision to engage in the development ofthe Ariane 5 ME, this modification to the Ariane 5 core to use twoVulcains is so comparitively low cost it could be done at the sametime as the Ariane 5 ME development. That is, you could have boththe Ariane 5 ME and the Ariane 6 in the same time frame.Another point, again as I discussed before, the mostimportant result of following this approach is that it would result ina manned capable launcher in a short time frame. Even if you areskeptical of the SSTO version, just using the current, small, ca. 10mTgross mass upper stage, or even smaller ones from the earlier versionsof the Ariane, you could have your manned launcher without the solidside boosters. This key advantage I still haven't seen discussed butobviously it would a great benefit in producing support among theEuropean public and the politicians, who hold the ESA purse strings.

Bob Clark

Note: the attached image did not appear in the AV Week article, at least it doesn't in the current version online. I found it after a web search. It does show two engines on the liquid fueled version of the Ariane 6 core.

_________________Single-stage-to-orbit was already shown possible 50 years ago with the Titan II first stage. Contrary to popular belief, SSTO's in fact are actually easy. Just use the most efficient engines and stages at the same time, and the result will automatically be SSTO.Blog: http://exoscientist.blogspot.com